The rare coin expert who is helping a California couple sell $10 million in gold pieces they dug up said Tuesday that there is no way the mother lode came from a 1900 heist at the San Francisco Mint.

That theory has been floating around since the so-called Saddle Ridge Hoard - a cache of 1,427 coins minted between 1847 and 1894 and buried under a tree in cans - came to light last week.

Larry Jackson has been collecting and selling rare coins for 40 years, and says his clients like to fly under the radar.

"Many people like to be very private about what they find, they don't want this kind of attention," said Jackson.

That's why he was surprised to see the massive coverage of the so called Saddle Ridge Hoard, found in a Northern California Couple's backyard.

The collection was on display in Atlanta last week, and had some coin collectors doing a double take.

"There's a lot of speculation that these coins could be out of a large coin robbery in San Francisco," Jackson said.

A local historian tracked down the newspaper article from January 1, 1900 reporting on the crime. At the time, $30,000 worth of gold pieces were stolen from the San Francisco Mint.

The couple in California found what would have then been worth $27,000 in gold coins from the same time frame.

Jackson says the similarities are too much to ignore.

"I think the gut reaction from most people in the numismatic fraternity is that this collection is probably from the US Mint cabinet and was stolen around 1899. Proving it is a different issue. But my gut tells me it came from that location," Jackson said.

But David McCarthy, senior numismatist for Kagin's, said it's about as likely as a three-dollar bill.

"It's provably incorrect," McCarthy told NBC News.

Even though the number and value of the coins swiped from a cashier's vault at the mint match the hoard, McCarthy reeled off a list of reasons they're not one and the same:

The mint's vault probably would have held bags containing coins from a single year with identical mint marks, but the hoard is much more diverse.

The hoard contains many coins that were heavily circulated, but the mint would have melted down and reissued those, not stored them.

There are 50 $10 gold coins in the hoard. Those were never mentioned in accounts of the mint heist, also known as the Dimmick Defalcation.

The hoard's coins don't have what experts call "bag marks," which they would expect to see on coins that had been vaulted for any length of time.

None of the hoard coins have dates after 1894, which would mean they would have been stored for six years at a minimum if they were from the mint job. "Who keeps 6-year-old inventory, especially of something that is not hard to get rid of?" McCarthy said.

Based on where the coins were discovered a year ago, McCarthy thinks they were amassed by someone doing a lot of a business in gold and who buried each can as soon as it was filled up, possibly over a span of 20 years.

An unexpected death would explain why they were abandoned - only to be found by the anonymous couple walking their dog on their property a century later.